This blog exists purely as a place for me to dump random links and thoughts I have rather than emailing them to my friends. It'll have large amounts of inside jokes. Also there will probably be times when I write "you" or refer to an email. Just pretend that you are reading an email to you. If you don't know me you likely won't find anything here interesting. If you do know me you also will not find anything here interesting.

Thursday, June 20, 2013

I bring you today another chapter in my ongoing saga to squeeze every last minute of life out of my laptop. About a month ago, my laptop randomly shut off. Investigation revealed that I had managed to rip open the power cord by getting it caught between a table and the concrete floor. I noticed that only bending the cable certain ways would cause the short. So, I did the logical thing and wrapped the cord in duct tape and forgot about it.

Fast forward to last night, and the power indicator tells me I'm running on battery power; the led on the power brick is off. I attempted to coax the cable into working, but to no avail. I shut my laptop off to preserve potentially precious battery and went to sleep.

Attempt 1

This morning I removed the duct tape bandage and began to examine the tear in the cable. The cable is similar to stereo cable from my last adventure, except (unbeknownst to me at this point) there is another layer of wire under the first.

I'll explain here that standard DC barrel connector have a ground and a positive voltage. The ground is the outside of the plug, and the positive is the inside. Similarly, in the cable, the ground is the outer wire, and then under an insulator there is the positive wire. These are both wound around a common axis (ie coaxial).

The outer wire was almost completely broken, so I cut it and attempted to splice it back together. The inner wire was in much better shape, with only a few broken strands. I at first attempted to just wrap that up, but ended up cutting it and splicing as well. I soldered these two up and used a multimeter to search for shorts between ground a positive. I powered it up and detected 19.5 V between the ground and positive.

However, booting up my laptop with it confirmed my suspicion that there was indeed a third inner wire. Dell conveniently adds their own third wire to standard DC cables for making more money through proprietary power adapter sales safety. This third wire was shorted to the positive and I figured whatever it was connected to in the power brick was now destroyed.

The third wire is a data wire. It sends a signal from the laptop to the adapter to make sure you are using an official dell adapter. If not it complains, but still powers the laptop. However, it does not charge the battery. There was some debate online about if the battery would indeed charge, just a slower rate, but I did not get any charge over the few hours I had it hooked up like this.

Attempt 2

It just so happens that I had procured a second power adapter long ago. In fact, this adapter was the second one. The first had failed a few years ago. It developed a noticeable kink near the power brick, and with that, presumably a short.

I decided to open it up and have a look. This video purports to show the adapter being opened. Note the comments accusing him of faking the opening. I'll agree that there is no way that was the first time he was opening the brick. It took me about an hour to get mine open, and I had to use just about every method I read online or could think of. I started with just a screwdriver, but that did nothing but tear up the plastic. I put some alcohol, and then acetone in the seam, which also did nothing but begin to dissolve the outer plastic. I hit it with a hammer on the corners, which along with constant attacks with the screwdriver did begin to weaken the adapters defenses. I only stabbed myself with the screwdriver three times before I put on a glove.

While the adapter was weakened, there were some parts that were clearly intent on making a valiant last stand. I ended up using a clamp to squeeze the bottom piece away from the top piece. This still required a constant attack with the screw driver. When it finally came apart, both parts of the plastic case looked like they had been gnawed on by a honey badger.

Now I pulled back the insulation to reveal the wire below. While this wire was about half broken it didn't seem like the second layer of insulation had any holes. It didn't seem like there was any short here.

I tested this with the multimeter and it confirmed the positive was separate from the ground. However, moving the cable around created a short. Further investigation revealed that the short was actually way up by the plug. This was rather annoying as I had hoped to use this better plug.

Attempt 3

I began to rip apart the plug to determine what was wrong with it. The rubber came off easily with a razor blade. Once off, it was clear that the insulation between the two wires stopped early and there was a short. I don't really know how this design could possibly work. It seems to be just begging for the insulation the wiggle its way down a mm and create a short.

The two wires were shrink tubed and soldered on to opposite sides of the plug. I had to get at least the ground wire free so that I could wrap the inner wire up to keep them separated. The problem was the wires were encased in something similar to hot glue, but much more rugged. I suspect it was just liquid plastic poured in.

It was quite strongly bonded to the shrink tubing. I tried acetone, which seemed to help, but I still had to chip away with screwdrivers and wire cutters little by little until the wire was free.

I wrapped the inner positive wire up in some electrical tape, and then wrapped the outer wire as well. I added several layers of duct tape around the whole thing for good measure.

Now I revisited the kink by the power brick. Here I decided to use a bit of solder to keep the broken half of the wire together. I did this and applied a generous amount of electrical tape.

I was pretty incredulous that this would produce a working cord. I did a lot of testing with the multimeter looking for shorts. Then I left it powered and did a thorough wiggle test. It passed both of those, so I plugged it into the laptop. The laptop recognized it as a fellow dell product and graced me by charging the battery.

Saturday, June 15, 2013

As promised I've gone through the data from IMDB for all the Star Trek series, and found the best episodes across all the series. I took the top 25% of episodes in each series and combined them. Then I cut it off to only those episodes that had a rating of 8 or above, which only cut off a dozen or so episodes. Here are the episodes, sorted by series and then air date. I'd add you should probably watch any two part episodes, even if they aren't listed, because they are usually both good and important to the plot. In DS9 the ending arc begins with S7E16, and even though some didn't make the cut, skipping any of those would be madness.

Tuesday, June 4, 2013

I have a pair of Logitech X-230 computer speakers that have served me well for close to 10 years now. One issue is that the cable that runs from the speakers to the computer is hardwired in. Recently, a wire failed and I was left with mono sound. While this was fine for fireside chats, music sounds much better in stereophonic sound.

I decided to open up the speaker and see how feasible adding a jack would be. The layout was simple enough. I identified where the wires connected to the circuit board and used a multimeter to determine which wire went to which part of the plug (tip, ring, bottom). I labeled the circuit board with my findings.

I then closed up the speaker and debated what to do. I could have easily just spliced in a new wire. The problem was I didn't like the idea of ruining a new wire, and I liked the idea of a jack for future flexibility.

The problem was I hadn't soldering in 10 years, and even then I had no idea what I was doing. I decided to learn how to solder and attempt this as a first project.

If you read the comments on that jack they are pretty bad. The only other choice at Sparkfun was this jack. Note that the first one is panel mount which meant it had a nut to hold it in a hole drilled in a panel. The second one would have to be held in place internally somehow.

This animatronic parot gave its life
so I could listen to Manowar

I watched a lot of soldering tutorials, and read some stuff. Then I found some solid wire from some old network cable I had, as well as some stranded wire from an old talking parrot toy I had. I made some splices and soldered them. With that I declared myself the world's foremost authority on soldering *.

The first order of business was removing the hot glue holding the audio cable in place. Following some internet advice I used some acetone and it released the cable immediately.

I cut the cable giving myself about 8 inches to work with inside the speaker. I tested the part that would remain inside the speaker to make sure the broken wire wasn't in there. I also stripped the ends of the other part so that I could use it for testing.

A quick note, there are three wires in a stereo audio cable. Right and left channel, and then a common ground. The ground is often bare wire twisted around the outside of the other two wires which serves as a shield. I just twisted up that part of the ground wire, with no regard for interference inside the speaker.

Now I had to install the jack. I drilled a hole in the side of the casing and put the jack in. However, as the comments had forewarned, the jack was not deep enough to fit through the wall. Actually it was just about perfect depth to fit, but with no space left over for the nut.

I thought about gluing it in place, but ended up drilling a slightly larger hole and then by pure luck having the nut fit perfectly in there. I then could screw in the jack to the nut. Once it was screwed in it was pretty much locked in place. This meant I had to do the soldering inside the speaker.

For some reason only the ground tab had a hole to thread the wire through. I probably should have drilled holes for the other two. It took about 3 hours to solder the wires on. Including soldering the first one on the wrong tab and then having to unsolder and then resolder it. The angle of the case made it very difficult to get the iron in a good position. The ground and another tab were quite close and I kept getting bridges between them. The ground wire with its holey tab took about 10 minutes.

I did a final test with the multimeter to make sure there were good connections from the solder points on the circuit board all the way to the bare ends of the audio cable.

I closed everything up and just about had a heart attack when an audio test revealed the left and right channels to be mixed up. Then I remembered that I don't care about the channels being correct, and as a result the speakers are physically on the wrong sides.

I must say the end result is about a billion times more professional looking than it should be.

Secret soldering expert?

* Note "the world" is the name I call my house. Even then this is a tenuous claim, as I believe my cat may have substantially more soldering knowledge than it is letting on.